The modern business environment is far from homogenous, and may be littered with a variety of heterogeneous policy enforcement points. These enforcement points may be either hardware based enforcement points such as XML Appliance or software counterparts such as a service intermediary enforcing default or custom policies at runtime. Each type of enforcement point has its own strength and weakness.
Hardware based approaches may use accelerators tweaked and optimized to process huge volumes of data. Some activities that may be carried out such as encryption or decryption and signature verification which are costly in terms of resources can therefore frequently better be carried out in hardware than software.
Such hardware based approaches may however be limited when it comes to extensibility, and in particular, for example, to defining and enforcing custom policies. This can be a difficulty when enforcing runtime governance in distributed service oriented architecture solutions using hardware based approaches.
The issue of service level agreement (SLA) enforcement may also be addressed. For a given service, a service provider may have a variety of service level agreements with different users and groups. The service provider may need to monitor and enforce these agreements using runtime policies configured to track and generate data to verify compliance with agreed terms. Different policy enforcement points may typically vary in their ability to enforce policies.
In brief, policy enforcement may involve considerable heterogeneity in a number of respects.
The figures are schematic and not to scale. The same or similar components are given the same reference number in different figures and the description relating thereto is not necessarily repeated.